DS-3571 Log hibernate validation errors

[tomdesair]

Problem

This problem was detected in DS-3571.

If there is a problem with the database schema (e.g. because of custom database modifications or a Flyway migration that was not executed due to incorrect config), the DSpace logs only output this:

2017-06-13 10:33:12,067 INFO  org.hibernate.tool.hbm2ddl.TableMetadata @ HHH000261: Table found: public.resourcepolicy
2017-06-13 10:33:12,068 INFO  org.hibernate.tool.hbm2ddl.TableMetadata @ HHH000037: Columns: [end_date, dspace_object, rptype, resource_type_id, policy_id, eperson_id, action_id, epersongroup_id, start_date_bkp, rpdescription, rpname, start_date]
2017-06-13 10:33:12,068 FATAL org.dspace.core.Context @ Cannot obtain the bean which provides a database connection. Check previous entries in the dspace.log to find why the db failed to initialize.

If you run a CLI script, you just see a NullPointerException printed on the console.

Solution

This PR adds information on the validation error:

• In the logs:

2017-06-13 10:52:13,087 INFO  org.hibernate.tool.hbm2ddl.TableMetadata @ HHH000261: Table found: public.resourcepolicy
2017-06-13 10:52:13,088 INFO  org.hibernate.tool.hbm2ddl.TableMetadata @ HHH000037: Columns: [end_date, dspace_object, rptype, resource_type_id, policy_id, eperson_id, action_id, epersongroup_id, start_date_bkp, rpdescription, rpname, start_date]
2017-06-13 10:52:13,088 FATAL org.dspace.core.Context @ Cannot obtain the bean which provides a database connection. Check previous entries in the dspace.log to find why the db failed to initialize. The schema validator returned: Wrong column type in public.resourcepolicy for column start_date. Found: timestamp, expected: date

• On the CLI:

INFO: Using dspace provided log configuration (log.init.config)
INFO: Loading: .../dspace6/config/log4j.properties
Exception: The schema validator returned: Wrong column type in public.resourcepolicy for column start_date. Found: timestamp, expected: date
org.dspace.core.exception.DatabaseSchemaValidationException: The schema validator returned: Wrong column type in public.resourcepolicy for column start_date. Found: timestamp, expected: date
	at org.dspace.core.Context.init(Context.java:170)
	at org.dspace.core.Context.<init>(Context.java:138)

Testing

Before starting Tomcat or any other CLI statement, update the DSpace database schema, e.g. alter table resourcepolicy alter column start_date type timestamp;

Then start Tomcat or run a DSpace CLI command. You should see an error describing why the database connection failed to start.

[hardyoyo]

Tested in Vagrant-DSpace, it's a nice improvement, however, it doesn't really address DS-3571, though it is helpful in that regard. I like this PR very much, though, and it's the kind of thing we need more of, so I'm approving it as-is.

[hardyoyo]

If we merge this into 6x, we'll need to port it forward to master.

[terrywbrady]

+1, verified locally using tomcat restart (rather than CLI)

[terrywbrady]

@tomdesair , thank you for the clear instructions for testing. They were very helpful.